1. Field of the Invention
The present invention relates to a method of continuous production of polycarbonate powder, and more particularly to a process of producing polycarbonate powder from a polycarbonate solution by concentrating and gelling the polycarbonate solution, powdering the gelled solid polycarbonate, and then grinding and drying the obtained polycarbonate powder in a single processing zone.
2. Description of the Prior Art
Heretofore, various methods of preparing polycarbonate powder have been known. One known method comprises extruding melting polycarbonate after the solvent has been eliminated by heating a polycarbonate solution and then grinding the extruded material (Japanese Patent Publication Nos. 22,890/1961 and 24,724/1963). Another known method is where gelation is achieved in a solvent or hot water and then the obtained gell is kneaded to form a powder (Japanese Patent Publication Nos. 21,033/1961, 11,031/1969 and 9,875/1970). A still further known method is where a polycarbonate solution and a steam mixture are brought into a turbulence zone (Japanese Patent Publication Nos. 3,533/1965 and 9,843/1965).
The known methods described above require a special apparatus for each process step such as concentration of a polycarbonate solution, powdering, grinding and drying. Therefore, they have such defects as difficulty in performing the processes in a short period of time and difficulty in preparing good quality powder, due to incomplete elimination of solvent or moisture.